The Analysis Of Reducing The Deviation Rate Of The Main Transformer Insulating Oil Chromatography Test

Power transformer is one of the most important power equipment in electric powersystem, whose safe operation is a key to the reliability of power supply and the reduction ofthe test and maintenance. Kinds of faults happen inside transformer are often accompanied byirrational and chemical reaction process, the products of which include the gas dissolvedinside the transformer insulating oil. Therefore, the fault types of transformers can bediagnosed by judging the operating state of transformer through the detection and analysis ofthe gas composition inside transformer insulating oil. Regular oil chromatographic analysis isa mature scheme. However, in the process of regular oil chromatographic analysis, thedeviation rates of the test results usually exceed the standard value of national regulationswhen test on the same sample for several times. It influences judgment of running state anddiagnosis of fault severely.Firstly, this paper adopts brain storming method to enumerate the reasons of oversizeddeviation rate based on the principle and work process of transformer insulating oilchromatographic analysis, and then restrict the cause in chromatographic instrument accuracy,sampling process sealing and containers sealing with the exclusive method. Secondly thispaper designs corresponding experiments respectively according to the three kinds of reasonsand carry on the deviation rate analysis. The result indicates the main reasons of the oversizeddeviation rate of regular oil chromatographic experiment is the dysfunction of samplingprocess sealing and containers sealing. Besides, vibration of the automobile during the sampletransportation accelerates the precipitation of gas composition inside the sample.According to the analysis results above, this paper improves the chromatography testmethod in the following two main ways: one is to improve sampling tools, and choose bettersealing containers and sampling channel to take sample, ensuring that the sample fromsampling to the laboratory be under a good sealed environment; The other is to simplify theexperiment process with new tools, and finally achieves the goal to reduce experimentaldeviation rate. This paper illustrates how to improve insulating oil chromatography test; givesup the glass bottle sampling method which has already been used for a long time and adoptssyringe sampling method. According to the particularity of transformer oil valve in a certainarea in Pearl River Delta, this paper makes matching sampling tools for transformers, thenimproves the particularity of the oil valve directly, and simple oil on site instead of which wasaccomplished in lab, and remain the gas composition in insulating oil to the largest extent,lying down a solid foundation for accurate judgment of all kinds of main transformer operation faults. Based on improved test methods, this paper analyses test errors of maintransformer’s insulating oil in a certain area’s several substation in Pearl River Delta andfinally draws a conclusion that new measures this paper takes reduce deviation rate of oilchromatographic analysis greatly.